// Copyright 2017 gf Author(https://gitee.com/johng/gf). All Rights Reserved.
//
// This Source Code Form is subject to the terms of the MIT License.
// If a copy of the MIT was not distributed with this file,
// You can obtain one at https://gitee.com/johng/gf.

package gdb

import (
    "fmt"
    "errors"
    "database/sql"
    "gitee.com/johng/gf/g/util/gconv"
    _ "github.com/go-sql-driver/mysql"
)

// 数据库链式操作模型对象
type Model struct {
    tx            *Tx           // 数据库事务对象
    db            *Db           // 数据库操作对象
    tables        string        // 数据库操作表
    fields        string        // 操作字段
    where         string        // 操作条件
    whereArgs     []interface{} // 操作条件参数
    groupBy       string        // 分组语句
    orderBy       string        // 排序语句
    start         int           // 分页开始
    limit         int           // 分页条数
    data          interface{}   // 操作记录(支持Map/List/string类型)
    batch         int           // 批量操作条数
}

// 链式操作，数据表字段，可支持多个表，以半角逗号连接
func (db *Db) Table(tables string) (*Model) {
    return &Model {
        db     : db,
        tables : tables,
        fields : "*",
    }
}

// 链式操作，数据表字段，可支持多个表，以半角逗号连接
func (db *Db) From(tables string) (*Model) {
    return db.Table(tables)
}

// (事务)链式操作，数据表字段，可支持多个表，以半角逗号连接
func (tx *Tx) Table(tables string) (*Model) {
    return &Model {
        tx     : tx,
        tables : tables,
    }
}

// (事务)链式操作，数据表字段，可支持多个表，以半角逗号连接
func (tx *Tx) From(tables string) (*Model) {
    return tx.Table(tables)
}

// 链式操作，左联表
func (md *Model) LeftJoin(joinTable string, on string) (*Model) {
    md.tables += fmt.Sprintf(" LEFT JOIN %s ON (%s)", joinTable, on)
    return md
}

// 链式操作，右联表
func (md *Model) RightJoin(joinTable string, on string) (*Model) {
    md.tables += fmt.Sprintf(" RIGHT JOIN %s ON (%s)", joinTable, on)
    return md
}

// 链式操作，内联表
func (md *Model) InnerJoin(joinTable string, on string) (*Model) {
    md.tables += fmt.Sprintf(" INNER JOIN %s ON (%s)", joinTable, on)
    return md
}

// 链式操作，查询字段
func (md *Model) Fields(fields string) (*Model) {
    md.fields = fields
    return md
}

// 链式操作，condition，支持string & gdb.Map
func (md *Model) Where(where interface{}, args...interface{}) (*Model) {
    md.where     = md.db.formatCondition(where)
    md.whereArgs = args
    return md
}

// 链式操作，添加AND条件到Where中
func (md *Model) And(where interface{}, args...interface{}) (*Model) {
    md.where     += " AND " + md.db.formatCondition(where)
    md.whereArgs  = append(md.whereArgs, args)
    return md
}

// 链式操作，添加OR条件到Where中
func (md *Model) Or(where interface{}, args...interface{}) (*Model) {
    md.where     += " OR " + md.db.formatCondition(where)
    md.whereArgs  = append(md.whereArgs, args)
    return md
}

// 链式操作，group by
func (md *Model) GroupBy(groupBy string) (*Model) {
    md.groupBy = groupBy
    return md
}

// 链式操作，order by
func (md *Model) OrderBy(orderBy string) (*Model) {
    md.orderBy = orderBy
    return md
}

// 链式操作，limit
func (md *Model) Limit(start int, limit int) (*Model) {
    md.start = start
    md.limit = limit
    return md
}

// 链式操作，操作数据记录项，可以是string/Map, 也可以是：key,value,key,value,...
func (md *Model) Data(data...interface{}) (*Model) {
    if len(data) > 1 {
        m := make(map[string]interface{})
        for i := 0; i < len(data); i += 2 {
            m[gconv.String(data[i])] = data[i + 1]
        }
        md.data = m
    } else {
        md.data = data[0]
    }
    return md
}

// 链式操作， CURD - Insert/BatchInsert
func (md *Model) Insert() (sql.Result, error) {
    // 批量操作
    if list, ok :=  md.data.(List); ok {
        batch := 10
        if md.batch > 0 {
            batch = md.batch
        }
        if md.tx == nil {
            return md.db.BatchInsert(md.tables, list, batch)
        } else {
            return md.tx.BatchInsert(md.tables, list, batch)
        }
    }
    // 记录操作
    if md.data == nil {
        return nil, errors.New("inserting into table with empty data")
    }
    if dataMap, ok :=  md.data.(Map); ok {
        if md.tx == nil {
            return md.db.Insert(md.tables, dataMap)
        } else {
            return md.tx.Insert(md.tables, dataMap)
        }
    }
    return nil, errors.New("inserting into table with invalid data type")
}

// 链式操作， CURD - Replace/BatchReplace
func (md *Model) Replace() (sql.Result, error) {
    // 批量操作
    if list, ok :=  md.data.(List); ok {
        batch := 10
        if md.batch > 0 {
            batch = md.batch
        }
        if md.tx == nil {
            return md.db.BatchReplace(md.tables, list, batch)
        } else {
            return md.tx.BatchReplace(md.tables, list, batch)
        }
    }
    // 记录操作
    if md.data == nil {
        return nil, errors.New("replacing into table with empty data")
    }
    if dataMap, ok :=  md.data.(Map); ok {
        if md.tx == nil {
            return md.db.Insert(md.tables, dataMap)
        } else {
            return md.tx.Insert(md.tables, dataMap)
        }
    }
    return nil, errors.New("replacing into table with invalid data type")
}

// 链式操作， CURD - Save/BatchSave
func (md *Model) Save() (sql.Result, error) {
    // 批量操作
    if list, ok :=  md.data.(List); ok {
        batch := 10
        if md.batch > 0 {
            batch = md.batch
        }
        if md.tx == nil {
            return md.db.BatchSave(md.tables, list, batch)
        } else {
            return md.tx.BatchSave(md.tables, list, batch)
        }
    }
    // 记录操作
    if md.data == nil {
        return nil, errors.New("saving into table with empty data")
    }
    if dataMap, ok :=  md.data.(Map); ok {
        if md.tx == nil {
            return md.db.Save(md.tables, dataMap)
        } else {
            return md.tx.Save(md.tables, dataMap)
        }
    }
    return nil, errors.New("saving into table with invalid data type")
}

// 链式操作， CURD - Update
func (md *Model) Update() (sql.Result, error) {
    if md.data == nil {
        return nil, errors.New("updating table with empty data")
    }
    if md.tx == nil {
        return md.db.Update(md.tables, md.data, md.where, md.whereArgs ...)
    } else {
        return md.tx.Update(md.tables, md.data, md.where, md.whereArgs ...)
    }
}

// 链式操作， CURD - Delete
func (md *Model) Delete() (sql.Result, error) {
    if md.where == "" {
        return nil, errors.New("where is required while deleting")
    }
    if md.tx == nil {
        return md.db.Delete(md.tables, md.where, md.whereArgs...)
    } else {
        return md.tx.Delete(md.tables, md.where, md.whereArgs...)
    }
}

// 设置批处理的大小
func (md *Model) Batch(batch int) *Model {
    md.batch = batch
    return md
}

// 链式操作，select
func (md *Model) Select() (List, error) {
    if md.fields == "" {
        md.fields = "*"
    }
    s := fmt.Sprintf("SELECT %s FROM %s", md.fields, md.tables)
    if md.where != "" {
        s += " WHERE " + md.where
    }
    if md.groupBy != "" {
        s += " GROUP BY " + md.groupBy
    }
    if md.orderBy != "" {
        s += " ORDER BY " + md.orderBy
    }
    if md.limit != 0 {
        s += fmt.Sprintf(" LIMIT %d, %d", md.start, md.limit)
    }
    if md.tx == nil {
        return md.db.GetAll(s, md.whereArgs...)
    } else {
        return md.tx.GetAll(s, md.whereArgs...)
    }
}

// 链式操作，查询所有记录
func (md *Model) All() (List, error) {
    return md.Select()
}

// 链式操作，查询单条记录
func (md *Model) One() (Map, error) {
    list, err := md.All()
    if err != nil {
        return nil, err
    }
    if len(list) > 0 {
        return list[0], nil
    }
    return nil, nil
}

// 链式操作，查询字段值
func (md *Model) Value() (interface{}, error) {
    one, err := md.One()
    if err != nil {
        return "", err
    }
    for _, v := range one {
        return v, nil
    }
    return "", nil
}